A closed-head brain injury, whether incurred as a result of blunt force trauma or a blast wave, can have insidious effects on a person. Although many casualties may suffer from headache or dizziness, it is difficult with conventional systems and methods to image every soldier or athlete in the field who experiences a potential brain injury. Most conventional imaging methods are large and require significant power. Moreover, damage to delicate brain tissues is frequently undetectable by conventional imaging, including CT scanning, even when such imaging is available.
The brain, however, is a soft organ with delicate structures held within a fixed volume. Damage to the small structures within a brain cause local swelling and cerebral blood flow and systemic blood pressure may not necessarily decrease with brain swelling. Therefore, even mild swelling of about 1 to 3 cc of extra fluid results in increased pressure. This elevated intracranial pressure (ICP) can itself cause more damage, including brain cell death and permanent brain injury or death.
In many active populations, especially true of the armed forces, or professional sports, a casualty may try to shrug off the seemingly mild symptoms of headache, dizziness, and the like. However, an unknown percentage of these injured are experiencing clinically significant elevated ICP which may worsen or result in permanent damage which could otherwise be avoided with the appropriate application of pharmacological or surgical interventions.
Currently, there is no known robust, portable, and reliable system or method which can accurately monitor ICP without direct access to the intracranial space. Therefore, it may not be feasible to check ICP on every person who has or may have experienced trauma to the brain. It is unknown how many casualties of blunt or blast trauma have underlying increased pressure in the brain that occurs in response to the injury.
The best conventional systems currently available to identify which casualties are at the most risk of brain injury are those that monitor the physical trauma (such as blast waves or impact) the head experiences. However, such conventional systems may only provide information based on an empirical diagnostic technique which may not take into account individual variability with regards to susceptibility of brain injury. Thus, two people experiencing the same physical trauma are likely to exhibit different levels of damage, but without a direct measure of the damage, they may be impossible to differentiate.
There are many conventional systems and methods that may hold promise for being able to measure or monitor ICP without direct access to the brain. These conventional systems and methods often employ large, heavy, power intensive equipment, such as MRI, and the like, and therefore are not portable. This limits their use in the battlefield or at the sidelines in sports related injuries.
The supraorbital artery provides an avenue of information from the cranial cavity. This vessel emanates from the internal carotid artery via the orbit and is readily accessible at the forehead. By virtue of its path along the periphery of the brain, it carries with it information related to the ICP. U.S. Pub. No. 2009/0143656 to Manwaring et al., discloses that the supraorbital artery may be used to determine ICP. However, as disclosed therein, only two sensors are used which may limit the accuracy of the measured ICP. Moreover, to date no practical device has emerged from the '656 patent application.
Thus, there is a need for a system and method that can measure ICP noninvasively, unobtrusively and continuously to provide an accurate measure of the extent of brain injury and enable medical care to timely provide the needed care. Moreover, in cases where the injury might have gone undetected until extensive damage has been done due to unchecked swelling, there is a need for effective threat agent that more quickly resolves the problem and returns the injured person to work, a soldier to duty, or an athlete to top performance.